Hill hasn’t played much the last few years – 15 attempts the last three seasons – but he played in 11 games in 2010 when Stafford missed most of the year with a shoulder injury. He completed 61.8 percent of his passes for 2,686 yards with 16 touchdowns and 12 interceptions that season.

He is widely considered to be one of the best backup quarterbacks in the league.

Hill, who turned 34 earlier this year, has provided the Lions with a comfortable second option at quarterback.

“You want to have, if you can, a guy that can step in there and win you a few games,” head coach Jim Caldwell said at the NFL Scouting Combine last month.

“You hope you never have to play him, that’s the key. You hope that your guy stays healthy, but the reality of it is that it may not happen so you’ve got to have a guy that’s capable in that spot.”

If Hill doesn’t return, the Lions will have to make a few decisions.

Do they bump Kellen Moore up from the No. 3 spot to the backup? Do they go try and sign another veteran free agent? Or do they draft a developmental quarterback?

Moore, who signed as a rookie free agent in 2012, has not been active for a regular-season game, which leaves a lot of question marks as to whether he’s ready to assume the backup role or not.

The Lions could also look to draft a quarterback in Day 3 and develop him in a new scheme. Caldwell, offensive coordinator Joe Lombardi and quarterbacks coach Jim Bob Cooter all have extensive experience developing the quarterback position.

Stafford has started 49 consecutive games, including the one playoff game in 2011, since suffering a few injury setbacks his first two years in the league.

He's proven to be extremely durable the last three seasons, but a solid backup plan is always key.

Caldwell knows that better than most after losing Peyton Manning for the entire 2011 season when he was head coach in Indianapolis. The Colts won just two games that season and Caldwell was let go after the season.